Drilling for oil and gas is becoming more and more complex. A precise steering control of the well is required to maximize reservoir contact for increased production and to assure consistent quality of the wellbore. Technologies like rotary steerable systems (RSS) enable drilling of complex three-dimensional wells. Typically, wells are not just vertical but have long horizontal sections for increased reservoir contact which may extend over several kilometers.
Model-based control has shown to be an effective control approach, but modeling the drilling process is challenging due to the complex interaction between drilling-bit and rock, and to the limited transfer of information between the surface and the drilling-bit, furthermore measurement of system states are effected by noise and time delays and model parameters are unknown and are space-variant.
The Moving Horizon Estimation (MHE) is a versatile algorithm that can be used for state and parameter estimation. The MHE uses measurement data in order to estimate the best value of state and parameters. A first version of an MHE algorithm has already been implemented in Matlab/Simulink.
The goals of this master's thesis are: